[Role of X-ray CT in diagnosis of ovarian tumor].

The utility of X-ray CT for the preoperative differentiation of benign and malignant ovarian tumors was investigated. Preoperative CT findings on 137 cases pathohistologically diagnosed as ovarian tumors, both benign and malignant, were compared. Dermoid cysts (42 cases) showed characteristic CT images and CT numbers, facilitating diagnosis. In CT findings of tumors (95 cases) other than dermoid cysts, (1) 70.8% of cystic tumors with protrusion from the cyst walls, and 92.9% of solid tumors with fluid parts with malignant; (2) 59.3% of tumors whose major axes measured on the CT image were 15 cm or longer were malignant; (3) all the tumors in which ascites was found on CT, and 46.2% of the tumors with enlargement of the other ovary observed by CT, were malignant; and (4) the CT number of the tumor fluid was 18.26 +/- 13.10 HU for the benign and 20.64 +/- 7.49 HU for the malignant tumors, and that of the solid parts was 51.67 +/- 16.80 HU for the benign and 37.73 +/- 10.34 HU for the malignant ones, showing different distribution areas. The CT findings were retrospectively scored by the use of Hayashi's quantification theory type II, and 93.2% of the benign-malignant differentiation rate was obtained.